RFR: 8366780: Enhance ProcSmapsParser and Printer to handle THPeligible field [v2]

[Stefan Johansson]

On Fri, 5 Sep 2025 06:23:04 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

>> src/hotspot/os/linux/procMapsParser.hpp line 52:
>> 
>>> 50:   size_t anonhugepages;
>>> 51:   size_t swap;
>>> 52:   size_t thpeligible;
>> 
>> Why `size`? Its name sounds like `bool`?
>
> Yes, it works like a `bool` but I represented it as a number to simply do the parsing similar to the other fields, but I guess I could handle it more like how `VmFlags` are handled.
> 
> The the parsing would then look like this, would you prefer that:
> 
> if (strncmp(_line, "THPeligible:", 12) == 0) {
>   out.thpeligible = ::strstr(_line + 12, "1") != nullptr;
>   return;
> }
> 
> 
> I think I would =)

Or actually make use of the unused ìnt` in the code, which I now when looking at the old review realize was used for the THPeligible field (but that parsing was then later removed). 

I'll push a change which does: 

  // scan THPeligible into a bool
  int thpel = 0;
  if (::sscanf(_line, "THPeligible: %d", &thpel) == 1) {
    out.thpeligible = (thpel == 1);
    return;
  }

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PR Review Comment: https://git.openjdk.org/jdk/pull/27098#discussion_r2324269607